This invention relates to a grinding machine for foodstuffs such as meat, and more particularly to a recovery system for an orifice plate-type grinding machine that includes a hard material collection arrangement.
A typical grinding machine includes a hopper that receives material to be ground and an advancement mechanism such as a rotatable auger that conveys the material away from the hopper toward a grinding head. The grinding head typically includes a discharge opening or outlet within which an orifice plate is positioned. A knife assembly is located between the end of the auger and the orifice plate, and is typically engaged with the auger and rotatable in response to rotation of the auger. The knives of the knife assembly cooperate to shear the material as it is forced through the orifices of the orifice plate.
Systems have been developed for the purpose of preventing hard material from passing through the orifices of the orifice plate. In a meat grinding application, for example, such systems function to route hard material such as bone, gristle and sinew away from the grinding orifices of the orifice plate. Representative hard material collection systems are shown and described in U.S. Pat. No. 7,461,800 issued Dec. 9, 2008; U.S. Pat. No. 5,344,086 issued Sep. 6, 1994; U.S. Pat. No. 5,289,979 issued Mar. 1, 1994; and U.S. Pat. No. 5,251,829 issued Oct. 12, 1993, the entire disclosures of which are hereby incorporated by reference. Typically, hard material collection systems of this type route the hard material to collection passages located toward the center of the orifice plate, where the hard material is supplied to a discharge tube or the like.
The hard material that is discharged through the collection passages is typically contained within a mixture that includes both hard material and soft, usable material. Various arrangements have been developed to recover the soft, usable material within the mixture, some of which are shown and described in the above-noted patents.
It is an object of the present invention to provide an improved system for recovering the soft, usable material in the mixture of hard and soft material that is discharged from hard material collection passages in an orifice plate-type grinding machine. It is another object of the invention to provide such a system that requires little or no adaptation of the grinding components of the grinding machine. It is a further object of the invention to provide such a system that is capable of adjustment for accommodating different types of material.
In accordance with the present invention, a recovery arrangement for a grinding machine is in the form of a separator assembly located downstream of the orifice plate of the grinding machine. The separator assembly includes an upstream inlet that receives the mixture of soft material and hard material from the collection passages of the orifice plate, in combination with a separator chamber having a wall that defines an axially extending tapered separator passage. The separator passage receives the mixture of soft material and hard material from the upstream inlet. The wall of the separator chamber includes a series of perforations that communicate between the separator passage and an outer surface defined by the wall. The separator assembly further includes a separator screw disposed within the separator passage of the separator chamber. The separator screw is interconnected with the rotatable advancement member and is rotatable within the separator passage in response to rotation of the rotatable advancement member. Rotation of the separator screw causes separation of soft material from the mixture of soft material and hard material, and forces the soft material through the perforations in the wall of the separator chamber. The separator chamber defines a downstream end that includes an outlet for discharging hard material.
The separator assembly may include an open support extending outwardly from the grinding head, and the separator chamber is engaged with and supported by the support at a location downstream of the orifice plate. In one embodiment, a centering pin extends from the rotatable advancement member. The centering pin rotates with the rotatable advancement member and is engaged within a center opening defined by the orifice plate, and the separator screw may be engaged with the centering pin so as to be rotatable with the rotatable advancement member via engagement with the centering pin. Engagement structure is interposed between the centering pin and the separator screw for non-rotatably securing the separator screw to the centering pin. An adjustment arrangement is operable to adjust the axial position of the separator screw within the separator passage, and the engagement structure between the separator screw and the centering pin is configured to accommodate axial movement of the separator screw relative to the centering pin by operation of the adjustment arrangement. Representatively, the engagement structure may be in the form of a bore in the separator screw within which the centering pin is received, a transverse passage in the centering pin, a slot in the separator screw that overlaps the transverse passage, and a transverse engagement pin that extends through the slot and the transverse passage. With this arrangement, the slot accommodates axial movement of the separator screw relative to the centering pin.
In one embodiment, the support and the orifice plate are configured and arranged to prevent axial movement of the separator chamber. The adjustment arrangement may be carried by the support and interconnected with the separator screw for providing axial movement of the separator screw within the separator passage. The adjustment arrangement may be in the form of an axially extending threaded adjustment member that extends through the support and into engagement with a threaded passage extending inwardly from a downstream end defined by the separator screw.
These and other objects, advantages, and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.